During arthroscopic surgery the flow of fluids and suction to the site must be controlled based on the surgeon's needs. Normally, fluid control is achieved with the use of a mechanical pump. Mechanical pumps have high initial costs plus maintenance costs and there is always the possibility that, during surgery, a pump will fail. There is always a risk of electric conduction injury and a risk of compartment syndrome where fluid pressure in a compartment exceeds venous pressure causing a loss of circulation to a limb or muscle group. This risk can be even greater with some of the current mechanical fluid systems when fluid leaks into spaces outside the joint as occurs in acute trauma when there is communication between the joint and local soft tissue. The invention gravity controlled positive pressure, in combination with the various modes of flow, reduces this risk and can eliminate the need for a tourniquet, thereby also reducing tourniquet related injuries due to vascular compromise and postoperative lactic acid accumulation in a limb. More recently electronic controls for fluid devices have been shown to have faulty electronics and/or problematic software leading to FDA recalls of these devices, mandatory service calls or upgrades to avoid patient injury. These concerns raise the inherent cost of these devices and add the requirement of significant post-market surveillance while in use.
There is a need in the art for a fluid control device not relying on a mechanical pump, vacuum, elaborate feedback loops, constant service, programming updates or elaborate electronic controls that provides adequate flow, control of direction of the flow and control of the flow rate.
Existing electromechanical system are based on constant pressure or constant flow. Some devices have extra feedback loops or pressure controls that must be properly maintained and serviced for reliable use and patient safety. The invention has distinct advantages over such a system because it only replenishes fluid that flows out of the joint, decreasing the amount of soft tissue swelling during the course of the procedure. Also, the gravity based system creates positive pressure environment in the joint to decrease intraarticular bleeding. Also, the system has multiple modes of flow allowing for more ways to clear intraarticular debris in the joint. By virtue of the simplistic design and control apparatus, this is all possible without the use of an electronic controller, pump, vacuum or elaborate mechanical or electronic feedback loop.